Hello,
Kaspersky is one of the best applications you can install in terms of security. The question is not if you are 100% secure, but how hard is to infect a PC with Kaspersky on, and how good you have to be to do that.
I don't know what you mean with dark side, but in my case KIS (Kaspersky Internet Security) has been tested by me with success and with almost 100% efficacy, in porn sites, cracks, torrents, I am not a good example I go with frequency to these sites.
If dark side is dark web, Kaspersky extension is disposable for Thor. I don't go that much to dark web because almost every time I find child porno sites and that is a line i don't cross, so I have no interest in dark web, but I believe Kaspersky can protect you or your friend even there.